Upper respiratory infections

Children tend to get more respiratory infections such as colds than adults because they have not yet developed immunity to many viruses

UPPER RESPIRATORY TRACT INFECTIONS 

upper respiratory tract infections (URTI or URI), are diseases caused by an acute infection involving the upper respiratory tract: nose, sinuses, pharynx and larynx.

upper respiratory tract infection  is a non-specific term used to describe acute infections of the nose, sinuses, pharynx, larynx, trachea and bronchi. The prototype is the disease known by the name of common colds, which will be discussed here, in addition to pharyngitis, sinusitis, and tracheo-bronchitis. Influenza is a systemic disease involving the airways and should be distinguished from other URI.

  

CAUSES 

Viruses cause most Upper Respiratory tract Infections with rhinovirus, parainfluenza virus, coronavirus, adenovirus, RS virus, Coxsackievirus, and the influence accounted for the majority of cases.  Human Metapneumovirus was recently found to cause material URI. beta-hemolytic streptococcus group (GABHS) causes 5% to 10% of cases, pharyngitis in adults. Other less common causes of bacterial pharyngitis are C beta-hemolytic streptococcus group, Corynebacterium diphtheriae, Neisseria gonorrhoeae, Arcanobacterium haemolyticum, Chlamydia pneumoniae, Mycoplasma pneumoniae, and herpes simplex virus. Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and are the most common organisms that cause bacterial super-infection of virus in acute sinusitis.  Less than 10% of acute tracheobronchitis due to Bordetella pertussis, B. parapertussis, M. or C. pneumoniae pneumoniae.

SIGN AND SYMPTOMS 

Acute upper respiratory tract infections are fever, pharyngitis / tonsillitis is often called the flu, and their complications: sinusitis, otitis, laryngitis, bronchitis, and sometimes (even if the bronchi are generally classified as part of the lower respiratory tract.) Symptoms URI common cough, sore throat, runny nose, nasal congestion, headache, low fever, facial pressure and sneezing. Onset of symptoms usually begin 1-3 days after exposure to pathogenic microorganisms. The illness usually lasts 7-10 days.

Group A beta hemolytic streptococcal pharyngitis / tonsillitis (strep throat) presents with sudden onset of sore throat, painful swallowing and fever. Strep throat usually does not cause a runny nose, changes in voice or cough. pain and ear pressure caused by middle ear infection (otitis media) and redness of the eye caused by a viral conjunctivitis is often associated with upper respiratory infections.

DIAGNOSIS 

Upper respiratory tract infections are diagnosed on the type and duration of symptoms. cold symptoms last for months, but do not cause sinus problems, allergies may actually be related.

TREATMENT 

The preferred treatment of upper respiratory infections is rest and plenty of fluids. Over-the-counter cold, flu and sinus remedies and pain relievers may provide temporary relief from symptoms but does not reduce infection. Gargle with salt water can help relieve the symptoms of sore throat. Steaming bowl of soup can help relieve nasal congestion opening. Antibiotics are not effective in treating viral infections, and only prescribed if the cause is a bacterial symptoms, such as sore throat, tonsillitis, earaches, or sinus infections. The best treatment for laryngitis is to rest his voice. repeated periods of tonsillitis treated surgically remove the infected tonsils. Mild croup can be treated at home with rest, fluids and a humidifier. However, children are hard to beat the basin in the hospital. 

If you have an upper respiratory infection, take plenty of rest and fluids. Call your doctor if symptoms worsen or last more than a week. Keep mucous membranes moist with a humidifier and petroleum jelly around the nose. nosedrops Saline may also help loosen mucus. Your doctor may tell you how this solution and how to use it often. You can help prevent upper respiratory tract, avoiding touching your eyes, nose and mouth, which would spread the virus your hands have contacted.

Bacterial infection of the central nervous system can cause abscesses

INFECTIONS OF THE NERVOUS SYSTEM 

 

The central nervous system or central nervous system includes the brain, spinal cord and membranes. In certain circumstances, bacteria can penetrate the central nervous system areas. If this occurs, abscesses or empyemas may be established. In general, the CNS is well defended against infection. The spine and brain are sheathed in hard, protective membrane. The outer membrane, the dura, and the next layer, the arachnoid, totally covering the brain and spinal cord. However, these defenses are not absolute. In rare cases, bacteria have access to areas of central nervous system.

 

There are four main causes of infections of the central nervous system (CNS): bacteria, viruses, fungi and protozoa.

 

Bacterial infection of the central nervous system can cause abscesses and empyema (accumulation of pus). Abscesses have fixed boundaries, but no definable shape and size empyema. CNS infections are classified according to where they occur. For example, a spinal epidural abscess is located above the dura mater, and subdural empyema occurs between the dura and arachnoid injury. As the pus and other material of an infection accumulate, pressure is exerted on the brain or spinal cord. This pressure can damage the nervous system tissue, perhaps permanently. Without treatment, CNS infection is fatal.

The brain is highly protected, and is essential for the maintenance of life. Yet the central nervous system infections are occurring. They range from a latent is rapidly fatal. This guide describes some of the features of CNS infection and laboratory diagnosis. The membranes surrounding the brain infections called meningitis. When the content of the brain that is infected with meningitis. brain abscesses are defined, localized lesions within the brain. "Slow" brain infections also occur, and these are usually fatal. Rapid diagnosis of CNS infections is important because many of the central nervous system infections are life threatening.

 

Viruses that infect the central nervous system (brain and spinal cord) include herpesviruses, arboviruses, coxsackieviruses, echoviruses and enteroviruses. Some of these infections primarily affect the meninges (the tissues covering the brain and spinal cord) and the result of meningitis. Others affect primarily the brain and cause encephalitis. Infections that affect both the meninges and brain after a meningo-encephalitis. Meningitis is most common in children than is encephalitis.

The virus affects the central nervous system in two ways. They can directly infect and destroy cells of the central nervous system during acute illness. After recovery from an infection of the central nervous system or elsewhere in the body's immune response to infection sometimes causes secondary damage to cells that surrounds nerve. These secondary damage (postinfectious encephalomyelitis or acute disseminated encephalomyelitis) results in children having more symptoms weeks after recovery from acute illness.

 

Meningitis is usually caused by viruses. Viral meningitis is a self-limiting disease. Bacterial meningitis is much less common, but is a potentially fatal condition. Other organizations may be a rare cause meningitis, for example, spirochetes and fungi. Symptoms include fever, severe headache, neck stiffness and photophobia. Due to the severity of the condition, so it may be caused by a number of staff, fast and accurate diagnosis of the cause is essential for prompt initiation of appropriate treatment.

 

Fungal infections of the central nervous system (CNS) are increasingly diagnosed both in immunocompromised and immunocompetent persons. Sinocranial aspergillosis more frequently described from temperate countries, most often in otherwise immunocompetent individuals. The clinical syndromes as fungal infections of the central nervous system can present are protean and may involve most neuroaxis. Certain clinical syndromes are specific to certain fungal infections. The nose shape is the most common syndrome with zygomycosis and skull-base syndromes frequently in clinical syndromes in patients with aspergillosis sino-cranial. Sub-acute and chronic meningitis in patients infected with HIV are more likely to be due to cryptococcal infection. Early recognition of clinical syndromes in an appropriate clinical context, it is the first step towards full recovery in some of these infections. 

 

 

CONGENITAL INFECTIONS OF CENTRAL NERVOUS SYSTEM 

 

Although vaccines, new antimicrobial agents and improvement in hygiene practices, congenital infections remain a major cause of mortality and neurological morbidity in children long term worldwide. important players are Toxoplasma gondii, cytomegalovirus, Treponema pallidum, herpes simplex virus types 1 and 2, and rubella. In addition, several other agents, such as varicella-zoster, parvovirus B19, and Borrelia burgdorferi, which potentially can infect the fetus and result in the fetus. This paper provides an overview of these infectious disorders, and outlines current strategies for the treatment of acute and long-term treatment.

               

Infectious diseases

INFECTION AND INFECTIOUS DISEASE 

INFECTIOUS AGENTS 

The world is full of microorganism ,the vast majority of which are harmless to man and many of which are essential to life .Some of these organism live on or within human hosts: most of these form part of our normal flora and are benign passenger or symbiotes.A minority ,however ,ar pathogenic ,causing illness or even death to their host .It is thses viruses ,bacteria , protozoa ,and worms which are responsible for the infectious disease.

Infection remains the main cause of morbidity and mortality in man ,particularly in underdeveloped areas where it is associated with poverty and overcrowding .In the developed world increasing prosperity ,universal immunization and antibiotics have reduced the prevalence of infectious disease .However ,antibiotic -resistant strains of bacteria as well as viruses and ' new ' diseases such as human immunodeficiency virus ( HIV ) infection and variant Creutzfeldt-jakob disease ( vCJD) have emerged .Increased global mobility has aided the spread of infectious disease and allowed previously localized pathogens to establish themselves world-wide .Deteriorating social conditions in the inner city areas of our major conurbations have facilitated the resurgence of tuberculosis and other infection.Changes in farming and food-processing methods have controlled to an increase in the incidence of food and water-borne disease.

In the developing world successes such as the eradication of smallpox have been balance or outweighed by the new plagues.Infectious cause nearly 25% of all human deaths .Two billion people -one third of the world's population-are infected with tuberculosis ,250-300 million people catch malaria every year ,and 200 million are  infected with schistosomiasis .Infections are often multiple and there is synergy both between different infections ,and between infection and other factors such as malnutrition.Many of the infectious diseases affecting developing countries are preventable or treatable ,but continue to thrive owing to lack of money and political will.

INFECTIOUS AGENTS

The causative agents of infectious diseases can be divided into four groups.

Prions  are the most recently-recognized and the simplest infectious agents ,consisting of a single protein molecule.They contain no nucleic acid and therefore no genetic information : their ability to propagate within a host relies on inducing the conversion of endogenous protein into prion protein.

viruses  contain both protein and nucleic acid and so carry the genetic information for their own reproduction.However ,they lack the apparatus to replicate autonomously ,relying instead on "hijacking " the cellular machinary of the host .They are smalll ( usually less than 200 nanametres in diameter ) and each virus possesses only one species of nucleic acid ( either RNA or DNA ).

Bacteria  are usually though not always ,larger than viruses .Unlike the latter they have both DNA and RNA , with the genome encoded by DNA ,They are enclosed by a cell membrane ,and even bacteria which have adopted an intracellular existence remain enclosed within their own cell wall. Bacteria are capable of fully autonomous reproduction ,and the majority are not  dependent on host cells.

Eukaryotes are the most sophisticated infectious organism ,displaying sub-cellular compartmentalization .Different cellular functions are restricted to specific organelles ,e.g photosynthesis takes place in the choloroplast ,DNA transcription in the nucleus and respiration in the mitochondria ,Eukaryotic pathogens include unicellular protozoa ,fungi ( which can be unicellular or filamentous ) ,and multicellular parasite worms.

Other higher classes ,notably the insects and the arachnids ,also contain species which can parasitize man and cause disease .

       

Infection

INFECTION AND INFECTIOUS DISEASE

ORGANISM INTERACTION AND SOURCES OF INFECTION

HOST / ORGANISM INTERACTIONS

Each of us is colonized with huge numbers of micro-organism ( bacteria plus viruses ,fungi , protozoa , and worms ) with which we coexist .The relationship with some of these organism is symbolic ,in which both partners benefit ,while others are commensals , living on the host without causing harm .Infection and illness may be due to these normally harmless commensals and symbiotes evading the body's defences and  penetrating into abnormal sites.Alternatively ,disease may be caused by exposure to exogenous pathogenic organism which are not part of our normal flora.



The symptoms and signs of infection are a result of the interaction between host and pathogen .in some cases ,such as the early stages of influenza ,symptoms are almost entirely due to killing of host cells by the invading organism .Usually ,however ,the harmful effects of infection are due to a combination of direct microbial pathogenicity ,and the body's response to infection .In meningococcal septicemia ,for example ,much of the tissue damage is caused by cytokines released in an attempt to fight the bacteria .In a few instances , such as chronic South American trypanosomiasis ( Chaga's disease ) ,mortality is almost entirely immunological ,with the parasite itself having little effect once the inflammatory process has been triggered .



SOURCES OF INFECTION

The endogenous skin and bowel commensals can cause disease in the host ,either because they have been transferred to an inappropriate site ( e.g bowel coliforms causing urinary tract infection ) ,or because host immunity has been attenuated ( e.g candidiasis in an immune compromised host ) .Many infections are acquired from other people ,who may be symptomatic themselves or be asymptomatic carriers .Some bacteria ,like the meningococcus ,are common transient commensals ,but cause invasive disease in a small minority of those colonized .Infection with other organisms ,such as the hepatitis B virus ,can be followed in some cases by an asymptomatic but potentially infectious carrier state.



Zoonoses are infections that can be trasmitted from wild or domestic animals to man .Infections can be acquired in a number of ways : direct contact with the animal ,ingestion of meat or animal products , contact with animal urine or faeces ,aerosol inhalation ,via an arthropod vector ,or by inoculation of saliva in a bite person to person .



Most microorganisms do not have a vertebrate or arthropod host but are free-living in the environment . The vast majority of these environmental organisms are non-pathogenic ,but a few can cause human disease.Person to person transmission of these infections is rare .Some parasites may have a stage of their life cycle which is environmental ( for example the free-living larval stage of Strongyloides stercoralis and the hookworms ) even though the adult worm requires a vertebrate host.Other pathogens can survive for periods in water or soil and may be transmitted from host to host via this route ,these should not be confused with true environmental organisms.



World -wide mortality from infectious disease such as :

• Acute lower respiratory infections
• HIV/AIDS.
• Diarrheal disease.
• Tuberculosis.
• Malaria.
• Measels.
• Tetanus.
• Whooping cough.
• Meningitis.
• Leishmaniasis.

Infectious endocarditis

INFECTIOUS ENDOCARDITIS 

Infective endocarditis is a form of endocarditis caused by infectious agents. Agents are usually bacteria, but other agencies may also be responsible. Heart valves do not receive the blood supply is engaged. Consequently, immune defense mechanisms (such as white blood cells) can not directly reach the valve through the bloodstream. If an organism (like bacteria) binds to a valve surface and forms of vegetation, the host immune response is blunted. The lack of blood supply to the valve also has implications for treatment, because medicines are also difficult to reach the infected valve. Normally, blood flows smoothly through these valves. If damaged - rheumatic fever, for example - the risk of bacterial adhesion is higher.

Infective endocarditis (IE) is an infection of the endocardial surface of the heart. The impact of this infection include severe valvular regurgitation intracardiac, which can lead to intractable congestive heart failure and myocardial abscesses. IE also produces a wide variety of systemic signs and symptoms through several mechanisms, including both sterile and infected emboli and various immunological phenomena.

There are several ways to classify endocarditis. The simplest classification is based on the causes of this disease , whether infected or not the infection, depending on whether the organism causes inflammation. Regardless, the diagnosis of endocarditis on the basis of clinical features, investigations such as cardiac ultrasound, as well as all blood cultures demonstrated the presence of micro-organisms that cause endocarditis.

PATHOPHYSIOLOGY 

Though uncertain, it is believed that the heart valve  of infective endocarditis and other surfaces  of heart when exposed to bacteria or fungi microemboli moves into the bloodstream. Dextran-producing bacteria for example Streptococcus mutans, a virulence factor in promoting compliance with the endovascular surfaces. Coagulase-negative staphylococci to produce biofilm is a prosthetic surface, which also contribute to a commitment. beta-hemolytic streptococci and enteric gram-negative bacteria is recognized factors such as respect, and seems less likely to cause blood poisoning. Endocardial surface is already damaged heart valve disease, endocarditis, surgery, or pacemaker wires create a favorable environment for the formation of thrombi. Over time, microorganisms multiply in whirlwinds, which is a classic vegetation. Micro-organisms to be put into circulation, usually continuously, which often leads to interesting results.

CAUSES 

The infection of the heart valve relatively resist by normal structure. Bacteria and fungi are not easy to attach to the endocardial surface, and constant good blood supply can prevent it from depositing in the structures of the endocardium. Thus, two factors generally required for  infective endocarditis: predisposing alteration of the endocardium and microorganisms in the bloodstream (bacteremia).  In a rare cases , bacteremia or mass of microorganisms specifically virulent cause of endocarditis on normal valves of the heart.

Endocarditis commonly involves the cardiac valves. The main predisposing factors are congenital heart defects, rheumatic valve disease, bicuspid or calcific aortic, mitral valve prolapse and hypertrophic cardiomyopathy. artificial valves are at particular risk. Sometimes, the sites of mural thrombus, ventricular septal defects and patent ductus arteriosus will be infected. The actual nidus of infection is usually a sterile fibrin-platelet vegetation ,it can formed when tissue factor release by damaged endothelial cells.

The microorganisms that infect the some layer of heart ( endocardium ) can originate from distant infected sites (example, skin abscesses, inflammation or infection of the gums, urinary tract infection) or visible portals of entry like in a central venous catheter or an injection site . Almost all the foreign material implanted (eg, ventricular peritoneal implants) runs the risk of bacterial colonization, thereby becoming a source of infection and therefore endocarditis.  Infective Endocarditis can also be asymptomatic bacteremia, as  occurs during invasive dental procedures, medical or surgical procedures. Even brushing your teeth, chewing, can cause septicemia (usually due to Streptococcus viridans) in gingivitis patients........ read more

Endocarditis treatment

It rapidly damages cardiac sites seeds extra-cardiac sites hematogenously and can progress to death within weeks ,incidence increases in elderly 

The incidence of infective endocarditis in the general population is estimated  approximately at 2 and 6 cases of 100 000 person-years, but significantly higher in patients with underlying valvular heart disease and the abuse of intravenous drugs. In addition, invasive procedures are performed also technically strong health care system can cause infections of the bloodstream and cause blood poisoning. Although historically rheumatic  valvulitis has often been regarded as a predisposing factor in endocarditis, times have changed. mitral valve prolapse, bicuspid aortic disease and aortic valvular heart disease are now the most frequent causes. Furthermore, the prosthetic valve heart defects in about one third of all cases of endocarditis, and affects 1% to 3% of patients after cardiac valvular surgery.

SIGN AND SYMPTOMS

In many cases the infection develops very slowly. Sometimes called subacute bacterial endocarditisor SBE. Symptoms can develop gradually, over weeks or months and may be vague. You tend to feel generally unwell and may have general aches and pains, fatigue, and may be out of food. The fever (high temperature) develops at some point in most cases. In these early symptoms may be caused by many other conditions, the cause of the symptoms can not be diagnosed for a while. Murmurs tend to develop heart. These are sounds that can be heard by a doctor listens to your heart with a stethoscope. murmurs are caused by an abnormal flow of blood through faulty valves or damaged. If you already have a murmur heart of an existing valve problem, the murmur may change or become more intense. A new murmur or change is often what alerts a physician to suspect infective endocarditis.

In some cases, the symptoms pretty quickly and it can be very bad for several days. Speed at which the disease develops depends in part on which bacteria or fungi that cause infection. Some bacteria are more virulent than others.



DIAGNOSIS

Infective endocarditis diagnosis based on symptoms, results of medical examinations and results of diagnostic tests:

Blood cultures show bacteria or microorganisms commonly found in endocarditis. blood cultures, blood tests can be time consuming for the laboratory to isolate specific bacteria causing the infection. Must be taken before antibiotics are started, if you have blood poisoning.

Echocardiogram (heart ultrasound) may show growths, abscesses (holes), the new regurgitation (leakage) or stenosis (narrowing), or an artificial heart valve that has begun to move away from the heart tissue. Occasionally, doctors insert an ultrasound probe in your esophagus or esophageal (TEE) to obtain a very detailed look at heart.

Other signs and symptoms of infective endocarditis included :

Emboli (small clots), bleeding (internal bleeding).
Stroke .
Shortness of breath .
Night sweats.
Loss of appetite or weight loss .
Muscle and joint pain


TREATMENT

When bacteria cause infective endocarditis , identified by blood culture tests ,Doc should start immediately intravenous (IV) antibiotic therapy. Intravenous antibiotics may be administered up to six weeks to control the infection. The symptoms will be monitored during treatment and blood tests to determine the effectiveness of treatment. If damage  of cardiac valves occurs, surgery may be needed to establish the heart valve and improve cardiac function.Treatment of infective endocarditis  starts with prevention. When endocarditis occurs, prompt treatment is necessary to prevent damage to heart valves and for more serious complications, including death...... read more

Rheumatic fever symptoms - Leptospirosis -Listeria symptoms

SYSTEMIC / MULTISYSTEM INFECTIONS 

RHEUMATIC FEVER 

Rheumatic fever is an inflammatory disease that can develop after an infection with Streptococcus bacteria (such as strep throat and scarlet fever) and can involve the heart (especially the valves), joints, skin and brain. Rare in developed countries like Great Britain, USA and Australia. Incidence has dropped by 10% of children in 1920 to 0.01% of all children today. This reduction in the incidence reflect advances in infection control and treatment of streptococcal infections to antimicrobials. The disease is still prevalent in developing countries such as the Middle and Far East and Latin America.

Rheumatic fever is preceded by a throat infection with Streptococcus organsisms. After infection with group A streptococcal pharyngeal, usually in childhood (5-15And) is followed by a systemic syndrome I think it is caused by an autoimmune reaction triggered by an infection. Syndrome includes: 1) Arthritis (multiple join pain and swelling) 2), carditis (heart inflammation) 3) The cutaneous manifestations 4) manifestations5 nervous system), fever, joint pain 50% etc.About Patients who develop carditis during the initial phase of the disease will continue to develop long-term heart disease and rheumatic valvular disease.

1) Blood tests: ESF and CRP (non-specific inflammation), leukocytosis2) Studies in X-ray may be a sign of heart infection, pericarditis, pericardial effusion effusion.3) ECG may signs of inflammation of the heart (extended range PR) or, and pericarditis (saddle-shaped ST elevation). Parts of the acute clinical syndrome may recur after the first period. However, projected common disease, skin disease and nerve disease associated with rheumatic fever is excellent with no known long-term consequences. rheumatic heart disease has traditionally been hailed as an important causal factor of cardiac valvular disease and makes the associated morbidity and mortality.

LEPTOSPIROSIS 

Leptospirosis is a rare infection, serious and contagious caused by bacteria of several species of the genus Leptospira, a micro-organism spiral (spirochete). Leptospirosis is often called the swineherd's disease, swamp fever, or mud fever. The organism enters the body when mucous membranes or abraded skin comes into contact with contaminated environmental sources. The infection causes a systemic disease that can often lead to renal and hepatic failure as possible. 

 Leptospirosis is a zoonosis (animal care) infection with a worldwide distribution and incidence. The incidence varies from sporadic in temperate zones endemic in some tropical countries. The disease has a seasonal incidence. Most cases occur during the rainy season in the tropics and in western countries in late summer or early fall, when soil is moist and alkaline. Leptospirosis is usually associated with tropical countries and heavy rains, but most cases occur in temperate climates, probably due to underreporting in some countries.

In general, the prognosis associated with this disease is good, usually with full recovery after infection. more serious systemic infections (Weil's disease), can lead to renal (kidney) or hepatic (liver), myocarditis (heart inflammation), and can be potentially fatal.

Approximately 15-40% of patients are exposed, but do not become ill show serologic (blood or urine or saliva) evidence of a past existing infection. This statistic includes 15% of abattoir workers, home workers, and the incubation period is usually between 7-12 days veterinarians.The, with a range of 2-20 days. About 90% of patients experience a mild form of the disease,
and about 5-10% have the severe form with jaundice, also known as Weil's disease. The natural course of leptospirosis is divided into two very distinct phases, sepsis and immune systems. For a brief period of 1-3 days between the first and second phase, the patient shows some improvement.

LISTERIOSIS 

Listeriosis is an infectious disease caused by foodborne bacteria Listeria monocytogenes. The symptoms are the symptoms of upper respiratory tract and septiceamia. Listeriosis is of particular concern during pregnancy because it can cause miscarriage, stillbirth, premature delivery and sepsis (full body infection) and pneumonia in newborns.

It is an environmental organization that is ubiquitous in soil and rotting matter.It affect both animals and humans, the most common way of infection to humans in contaminated food. The organism can grow at temerature as low as 4 degrees Celsius, and the foods most frequently implicated are soft cheeses, unpasteurized, raw vegetables and the chicken heads. Listeriosis is a rare but serious infection that mostly affects infants, pregnant women, elderly and immunocompromised, L. monocytogenes has also been recently recognized as a cause of self-limiting gastroenteritis, foodborne healthy adults, but the incidence of this phenomenon is unknown....... read more